1. Field of the Invention
The present invention relates to a sintered ceramic body, a manufacturing method of the sintered ceramic body, and a ceramic structure. More specifically the invention pertains to a low-temperature sintered ceramic body that is capable of being fired simultaneously with a low resistance metal, such as silver or copper, as a line conductor, as well as a manufacturing method of such a sintered ceramic boy and a ceramic structure.
2. Description of the Related Art
A conventionally proposed low-temperature sintered ceramic body that is capable of being fired simultaneously with a conductor includes quarts (SiO2) and hexagonal and monoclinic celsian (BaAl2Si2O8) in its crystalline phase and has B/A of not greater than 0.2 and C/A of not less than 0.6, where A represents an X-ray intensity of a quarts (101) face, B represents an X-ray intensity of a monoclinic celsian (112) face, and C represents an X-ray intensity of a hexagonal celsian (101) face (see, for example, Japanese Patent Laid-Open No. 2008-105917). This proposed sintered body is expected to have an increased coefficient of thermal expansion and an enhanced chemical resistance. Another proposed sintered ceramic body includes Al, Si, Sr, and Ba as primary components and has Al2O3 crystals and at least one of hexagonal SrAl2Si2O8, (Sr,Ba)Al2Si2O8, and BaAl2Si2O8 in the structure (see, for example, Japanese Patent Laid-Open No. 2006-001755). This proposed sintered body is expected to have an increased mechanical strength and an improved dielectric characteristic. Still another proposed sintered ceramic body has a content of glass powder in a range of 25% to 34% and a content of alumina ceramic power as a mixture of fine particles and coarse particles in a range of 66% to 75% and average particle diameters of the glass powder and the ceramic powder of less than 1 μm (see, for example, Japanese Patent Laid-Open No. 2001-010858). This proposed sintered body is expected to be densified by low-temperature sintering at a temperature of not higher than 1000° C.
Japanese Patent Laid-Open No. 2008-105917, however, has no description of the mechanical strength or the Q value representing the resonance characteristic of the sintered ceramic body. The sintered ceramic body disclosed in Japanese Patent Laid-Open No. 2006-001755 has requirement for adding Sr. Addition of Sr to the celsian composition may lead to a phase change from hexagonal celsian to monoclinic celsian and undesirably lower the mechanical strength. The sintered ceramic body disclosed in Japanese Patent Laid-Open No. 2001-010858 is densified by adjustment of the average particle diameter but has insufficient resonance characteristic, which requires a further increase of the Q value. It is thus required to lower the firing temperature and to enhance the mechanical characteristics and the resonance characteristics.
By taking into account the issue discussed above, there is a requirement for providing a sintered ceramic body having a lowered firing temperature and enhanced mechanical characteristics and resonance characteristics, as well as a manufacturing method of such a sintered ceramic body.